I'm not "too" worried about it but I figured they'd rather be roosting... Anything I'm missing?
Welcome to BYC!
My pullets did the same thing. Their first few weeks in the coop were spent on the floor 95% of the time. They were used to sleeping close to the floor thanks to their brooder arrangements and, when they moved to the coop with the large, high roosts, they didn't know what to do! So, I wouldn't worry too much. They'll get the hang of it. You might want to place them on the roost every evening to teach them that's where they are to sleep.